Polymer comprising repeat units with photoacid-generating functionality and base-solubility-enhancing functionality, and associated photoresist composition and electronic device forming method

ABSTRACT

A polymer includes repeat units, at least half of which are photoacid-generating repeat units. Each of the photoacid-generating repeat units includes photoacid-generating functionality and base-solubility-enhancing functionality. The polymer is useful as a component of a photoresist composition that further includes a second polymer that exhibits a change in solubility in an alkali developer under action of acid.

FIELD

The present invention relates to photoacid-generating polymers useful ascomponents of photoresist compositions.

INTRODUCTION

As feature sizes of integrated circuits continue to shrink, nextgeneration lithographic processes struggle to fit the stringentrequirements to extend Moore's Law. It has long been recognized thatincreased photoacid generator (PAG) non-uniformity and acid diffusionhave limited photoresist resolution, worsened line width roughness (LWR)(see, e.g., Nakamura et. al., Proc. SPIE 2013, 8682, 86821H-1), limitedexposure latitude, and generally degraded photolithographic performancefor chemically amplified resists. In the past, polymer-bound-PAG (PBP)systems have been implemented to increase PAG uniformity and controlacid diffusion (see, e.g., Oh et. al., Proc. SPIE 2008, 7140 714031,pages 1-9; and U.S. Pat. No. 5,945,250 B2 to Aoai et al.). Morerecently, increased concentration of PAG in the matrix has been shown tofurther enhance lithographic performance, particularly when combinedwith a PBP system (U.S. Patent Application Publication No. US2014/0080062 A1 of Thackeray et. al.). Despite these advances, thereremains a need for photoresist compositions providing one or more ofdecreased critical dimension uniformity, decreased dose to clear energy,and increased contrast slope.

SUMMARY

One embodiment is a polymer comprising, based on 100 mole percent oftotal repeat units, 50 to 100 mole percent of photoacid-generatingrepeat units, wherein each of the photoacid-generating repeat unitscomprises (a) photoacid-generating functionality and (b)base-solubility-enhancing functionality selected from the groupconsisting of tertiary carboxylic acid esters, secondary carboxylic acidesters wherein the secondary carbon is substituted with at least oneunsubstituted or substituted C₆₋₄₀ aryl, acetals, ketals, lactones,sultones, alpha-fluorinated esters, beta-fluorinated esters,alpha,beta-fluorinated esters, polyalkyleneglycols, alpha-fluorinatedalcohols, and combinations thereof.

Another embodiment is a photoresist composition comprising the polymerand a solvent.

Another embodiment is a method of forming an electronic device,comprising: (a) applying a layer of the photoresist composition on asubstrate; (b) pattern-wise exposing the photoresist composition layerto activating radiation; and (c) developing the exposed photoresistcomposition layer to provide a resist relief image.

These and other embodiments are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a synthetic scheme for the preparation of5-(3,5-dimethyl-4-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)phenyl)-5H-dibenzo[b,d]thiophen-5-ium((1S,4S)-7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate.

FIG. 2 is a synthetic scheme for the preparation of2-(2-methoxyethoxy)ethyl 4-tosylate.

FIG. 3 is a synthetic scheme for the preparation of2-(2-(2-methoxyethoxy)ethoxy)-1,3-dimethylbenzene.

FIG. 4 is a synthetic scheme for the preparation of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-dibenzothiophen-5-iumiodide.

FIG. 5 is a synthetic scheme for the preparation of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

FIG. 6 is a synthetic scheme for the preparation of5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

FIG. 7 is a synthetic scheme for the preparation of5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate.

FIG. 8 is a synthetic scheme for the preparation of5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

FIG. 9 is a synthetic scheme for the preparation of a homopolymer of5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

FIG. 10 is a synthetic scheme for the preparation of a homopolymer of5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate.

FIG. 11 is a synthetic scheme for the preparation of a homopolymer of5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

FIG. 12 is a synthetic scheme for the preparation of a copolymer of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate and5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate.

FIG. 13 is a synthetic scheme for the preparation of a copolymer5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate and5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

DETAILED DESCRIPTION

The present inventors have determined that the photolithographicperformance of a photoresist composition can be improved by theincorporation of a polymer that includes a majority ofphotoacid-generating repeat units, wherein each of thephotoacid-generating repeat units comprises photoacid-generatingfunctionality and base-solubility-enhancing functionality. Theimprovement in photolithographic performance can be manifested as one ormore of decreased critical dimension uniformity, decreased dose to clearenergy, and increased contrast slope.

Thus, one embodiment is a polymer comprising, based on 100 mole percentof total repeat units, 50 to 100 mole percent of photoacid-generatingrepeat units, wherein each of the photoacid-generating repeat unitscomprises (a) photoacid-generating functionality and (b)base-solubility-enhancing functionality selected from the groupconsisting of tertiary carboxylic acid esters, secondary carboxylic acidesters wherein the secondary carbon is substituted with at least oneunsubstituted or substituted C₆₋₄₀ aryl, acetals, ketals, lactones,sultones, alpha-fluorinated esters, beta-fluorinated esters,alpha,beta-fluorinated esters, polyalkyleneglycols, alpha-fluorinatedalcohols, and combinations thereof. When a chemical group ischaracterized as unsubstituted or substituted, the “substituted” versionthereof includes at least one substituent such as a halogen (i.e., F,Cl, Br, I), hydroxyl, amino, thiol, carboxyl, carboxylate, ester(including acrylates, methacrylates, and lactones), amide, nitrile,sulfide, disulfide, nitro, C₁₋₁₈ alkyl (including norbornyl andadamantyl), C₁₋₁₈ alkenyl (including norbornenyl), C₁₋₁₈ alkoxyl, C₂₋₁₈alkenoxyl (including vinyl ether), C₆₋₁₈ aryl, C₆₋₁₈ aryloxyl, C₇₋₁₈alkylaryl, or C₇₋₁₈ alkylaryloxyl. “Fluorinated” shall be understood tomean having one or more fluorine atoms incorporated into the group. Forexample, where a C₁₋₁₈ fluoroalkyl group is indicated, the fluoroalkylgroup can include one or more fluorine atoms, for example, a singlefluorine atom, two fluorine atoms (e.g., as in a 1,1-difluoroethylgroup), three fluorine atoms (e.g., as in a 2,2,2-trifluoroethyl group),or fluorine atoms at each free valence of carbon (e.g., as in aperfluorinated group such as —CF₃, —C₂F₅, —C₃F₇, or —C₄F₉).

In some embodiments, the polymer comprises, based on 100 mole percent oftotal repeat units, 60 to 100 mole percent of photoacid-generatingrepeat units, specifically 70 to 100 mole percent ofphotoacid-generating repeat units, more specifically 80 to 100 molepercent of photoacid-generating repeat units, still more specifically 90to 100 mole percent of photoacid-generating repeat units, even morespecifically 95 to 100 mole percent of photoacid-generating repeatunits. As used herein, the term “repeat unit” refers to divalent unitthat is the residue of a polymerizable monomer. Conversely, “repeatunit” does not include monovalent groups, such as a terminal groupderived from a polymerization initiator.

The photoacid-generating repeat units include photoacid-generatingfunctionality. The photoacid-generating functionality can be chemicallyneutral, in the sense that it does not include an anion or a cation.Examples of chemically neutral photoacid-generating functionalityinclude

Although the examples shown above are monovalent, thephotoacid-generating functionality can also be divalent, trivalent, ortetravalent, depending on the structure of the photoacid-generatingrepeat unit.

Alternatively, the photoacid-generating functionality can comprise acation and an anion. For example, the cation can comprise adihydrocarbyliodonium group or a trihydrocarbylsulfonium group, Forexample, the anion can comprise sulfonate (—SO₃ ⁻), sulfonamidate (anionof sulfonamide; —S(O)₂N⁻R³, wherein R³ is H or unsubstituted orsubstituted C₁₋₁₂ hydrocarbyl), or sulfonimidate (anion of sulfonimide;—S(O)₂N⁻S(O)₂R³, wherein R³ is H or unsubstituted or substituted C₁₋₁₂hydrocarbyl). As used herein, the term “hydrocarbyl”, whether used byitself, or as a prefix, suffix, or fragment of another term, refers to aresidue that contains only carbon and hydrogen unless it is specificallyidentified as “substituted hydrocarbyl”. The hydrocarbyl residue can bealiphatic or aromatic, straight-chain, cyclic, bicyclic, branched,saturated, or unsaturated. It can also contain combinations ofaliphatic, aromatic, straight chain, cyclic, bicyclic, branched,saturated, and unsaturated hydrocarbon moieties. When the hydrocarbylresidue is described as substituted, it can contain heteroatoms inaddition to carbon and hydrogen.

In addition to photoacid-generating functionality, eachphotoacid-generating repeat unit comprises base-solubility-enhancingfunctionality. Base-solubility-enhancing functionality includesfunctional groups that are base-soluble (e.g., polyalkyleneglycols,alpha-fluorinated alcohols); functional groups that are base-solubleafter acid-catalyzed deprotection (e.g., tertiary esters, acetals,ketals, secondary carboxylic acid esters wherein the secondary carbon issubstituted with at least one unsubstituted or substituted C₆₋₄₀ aryl);and functional groups that are base-soluble after base-catalyzeddeprotection (e.g., fluorinated esters, lactones, sultones). Examples ofbase-solubility-enhancing functionality include tertiary carboxylic acidesters, secondary carboxylic acid esters wherein the secondary carbon issubstituted with at least one unsubstituted or substituted C₆₋₄₀ aryl,acetals, ketals, lactones, sultones, alpha-fluorinated esters,beta-fluorinated esters, alpha,beta-fluorinated esters,polyalkyleneglycols, alpha-fluorinated alcohols, and combinationsthereof. In some embodiments, the base-solubility-enhancingfunctionality is a tertiary carboxylic acid ester, an acetal, a ketal, alactone, or a combination thereof. In some embodiments,base-solubility-enhancing functionality resides in thephotoacid-generating cation.

In some embodiments, the photoacid-generating repeat unit comprises apolymer-bound anion and a non-polymer-bound cation. For example, thephotoacid-generating repeat units can have the structure

wherein R¹ is independently in each of the repeat units H, F, —CN, C₁₋₁₀alkyl, or C₁₋₁₀ fluoroalkyl; L¹ is independently in each of the repeatunits —O—, —C(O)—O—, unsubstituted C₆₋₁₈ arylene, or substituted C₆₋₁₈arylene; m is independently in each of the repeat units 0 or 1; L² isindependently in each of the repeat units an unsubstituted orsubstituted C₁₋₂₀ hydrocarbylene, wherein the substituted C₁₋₂₀hydrocarbylene can, optionally, include one or more in-chain divalentheteroatom-containing groups such as —O—, —S—, —NR², —PR²—, —C(O)—,—OC(O)—, —C(O)O—, —OC(O)O—, —N(R²)C(O)—, —C(O)N(R²)—, —OC(O)N(R²)—,—N(R²)C(O)O—, —S(O)—, —S(O)₂—, —N(R²)S(O)₂—, —S(O)₂N(R²)—, —OS(O)₂—, or—S(O)₂O—, wherein R² is H or C₁₋₁₂ hydrocarbyl; Z⁻ is independently ineach of the repeat units sulfonate (—SO₃ ⁻), sulfonamidate (anion ofsulfonamide; —S(O)₂N⁻R³, wherein R³ is H or unsubstituted or substitutedC₁₋₁₂ hydrocarbyl), or sulfonimidate (anion of sulfonimide;—S(O)₂N⁻S(O)₂R³, wherein R³ is H or unsubstituted or substituted C₁₋₁₂hydrocarbyl); and Q⁺ is photoacid-generating cation; wherein at leastone of L¹, L² (when m is 1), and Q⁺ comprises thebase-solubility-enhancing functionality. In other words, if m is zero,then at least one of L¹ and Q⁺ comprises base-solubility-enhancingfunctionality, and if m is one, then at least one of L¹, L², and Q⁺comprises base-solubility-enhancing functionality.

In specific embodiments of the photoacid-generating repeat unitcomprising a polymer-bound anion and a non-polymer-bound cation, R¹ isindependently in each of the repeat units H or methyl; L¹ is —C(O)—O— ineach of the repeat units; m is 1 in each of the repeat units; L² isindependently in each of the repeat units a fluorine-substituted C₂₋₂₀hydrocarbylene, wherein the fluorine-substituted C₂₋₂₀ hydrocarbylenecan, optionally, include one or more in-chain divalentheteroatom-containing groups that is —O—, —OC(O)—, or —C(O)O—; Z⁻ issulfonate (—SO₃ ⁻) in each of the repeat units; and Q⁺ is independentlyin each of the repeat units an unsubstituted or substitutedtri(C₁₋₆₀-hydrocarbyl)sulfonium ion, or an unsubstituted or substituteddi(C₁₋₆₀-hydrocarbyl)iodonium ion. When R¹ is H and L¹ is —C(O)—O—, thenthe repeat unit is an acrylate ester. When R¹ is methyl and L¹ is—C(O)—O—, then the repeat unit is a methacrylate ester.

In some embodiments, the photoacid-generating functionality comprises apolymer-bound cation and a non-polymer-bound anion. For example thephotoacid-generating repeat units have the structure

wherein R¹ is independently in each of the repeat units H, F, —CN, C₁₋₁₀alkyl, or C₁₋₁₀ fluoroalkyl; L¹ is independently in each of the repeatunits —O—, —C(O)—O—, unsubstituted C₆₋₁₈ arylene, or substituted C₆₋₁₈arylene; m is independently in each of the repeat units 0 or 1; L² isindependently in each of the repeat units an unsubstituted orsubstituted C₁₋₂₀ hydrocarbylene, wherein the substituted C₁₋₂₀hydrocarbylene can, optionally, include one or more in-chain divalentheteroatom-containing groups that is —O—, —S—, —NR², —PR²—, —C(O)—,—OC(O)—, —C(O)O—, —OC(O)O—, —N(R²)C(O)—, —C(O)N(R²)—, —OC(O)N(R²)—,—N(R²)C(O)O—, —S(O)—, —S(O)₂—, —N(R²)S(O)₂—, —S(O)₂N(R²)—, —OS(O)₂—, or—S(O)₂O—, wherein R² is H or C₁₋₁₂ hydrocarbyl; P⁺ is independently ineach of the repeat units a monovalent group comprising an unsubstitutedor substituted tri(C₁₋₆₀-hydrocarbyl)sulfonium ion, or an unsubstitutedor substituted di(C₁₋₆₀-hydrocarbyl)iodonium ion; and X⁻ is a monovalentanion; wherein at least one of L¹, L² (when m is 1), and Q⁺ comprisesthe base-solubility-enhancing functionality.

In specific embodiments of the photoacid-generating repeat unitcomprising a polymer-bound cation and a non-polymer-bound anion, R¹ isindependently in each of the repeat units H or methyl; L¹ is —C(O)—O— ineach of the repeat units; P⁺ is independently in each of the repeatunits a monovalent group comprising an unsubstituted or substitutedtri(C₁₋₆₀-hydrocarbyl)sulfonium ion; and X⁻ comprises sulfonate (—SO₃ ⁻)in each of the repeat units. When R¹ is H and L¹ is —C(O)—O—, then therepeat unit is an acrylate ester. When R¹ is methyl and L¹ is —C(O)—O—,then the repeat unit is a methacrylate ester.

In some embodiments of the polymer, the photoacid-generating repeatunits are derived from a single monomer. Alternatively, thephotoacid-generating repeat units can be derived from at least twodifferent monomers.

The polymer comprises 50 to 100 mole percent of photoacid-generatingrepeat units, based on 100 mole percent of total repeat units. When thepolymer comprises less than 100 mole percent of photoacid generatingrepeat units, the other repeat units can comprise photoacid-generatingfunctionality or not, and they can comprise base-solubility-enhancingfunctionality or not. Examples of monomers from which such other repeatunits can be derived are

wherein each occurrence of R^(a) is independently H, F, —CN, C₁₋₁₀alkyl, or C₁₋₁₀ fluoroalkyl.

In some embodiments, the polymer has a weight average molecular weightof 2,500 to 10,000 daltons, specifically 3,000 to 7,000 daltons.

Another embodiment is a photoresist composition comprising the polymerand a solvent. Any of the variations described above in the context ofthe polymer apply as well to the photoresist composition comprising thepolymer. Suitable solvents include anisole; esters including ethyllactate, methyl 2-hydroxybutyrate (HBM), n-butyl acetate,1-methoxy-2-propyl acetate (also referred to as propylene glycol methylether acetate, PGMEA), methoxyethyl propionate, ethoxyethyl propionate,and gamma-butyrolactone; alcohols including 1-methoxy-2-propanol (alsoreferred to as propylene glycol methyl ether, PGME), and 1-ethoxy-2propanol; ketones including cyclohexanone and 2-heptanone; andcombinations thereof.

Another embodiment is a method of forming an electronic device,comprising: (a) applying a layer of the photoresist composition on asubstrate; (b) pattern-wise exposing the photoresist composition layerto activating radiation; and (c) developing the exposed photoresistcomposition layer to provide a resist relief image.

The invention is further illustrated by the following examples.

Example 1

FIG. 1 is a synthetic scheme for the preparation of5-(3,5-dimethyl-4-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)phenyl)-5H-dibenzo[b,d]thiophen-5-ium((1S,4S)-7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate.

5-(3,5-Dimethyl-4-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)phenyl)-5H-dibenzo[b,d]thiophen-5-ium((1S,4S)-7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate

5-(3,5-dimethyl-4-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)phenyl)-5H-dibenzo[b,d]thiophen-5-ium((1S,4S)-7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonatechloride (19.4 g, 35.6 mmol) and sodium camphorsulfonate (9.52 g, 37.4mmol) were dissolved in dichloromethane (200 mL) and water (200 mL) andstirred at room temperature overnight. The layers were separated and theorganic phase washed with water (6×150 mL) and concentrated. The crudesolid was dissolved in minimal dichloromethane, precipitated into methyltert-butyl ether (500 mL), filtered and dried to afford the titlecompound (19.0 g, 72%) as a white solid. ¹H NMR (500 MHz, (CD₃)₂CO) δ:8.52 (d, J=7.8 Hz, 2H), 8.33 (d, J=7.8 Hz, 2H), 7.97 (dt, J=8.4, 0.9 Hz,2H), 7.76 (dt, J=8.1, 0.9 Hz, 2H), 7.32 (s, 2H), 4.56 (s, 2H), 2.86 (d,J=17.7 Hz, 1H), 2.72 (t, J=7.5 Hz, 1H), 2.35 (d, J=17.7 Hz, 1H), 2.22(s, 6H), 2.13-2.28 (m, 2H), 1.44-1.97 (m, 26H), 1.26 (d, J=9 Hz, 1H).

Example 2

FIG. 2 is a synthetic scheme for the preparation of2-(2-methoxyethoxy)ethyl 4-tosylate.

2-(2-Methoxyethoxy)ethyl 4-tosylate

Sodium hydroxide (62 g, 1.55 mol) in water (350 mL) was carefully addedin one portion to 2-(2-methoxyethoxy)ethanol (110 g, 912 mmol) intetrahydrofuran (350 mL) at 0° C. under vigorous stirring and stirredfor 5 min. Then tosyl chloride (209 g, 1.09 mol) in tetrahydrofuran (350mL) was added over 10 minutes, warmed to room temperature and stirredfor 4 h. The reaction mixture was diluted with water (350 mL) andextracted with methyl tert-butyl ether (2×700 mL). The combined organiclayers were washed with 1M aqueous sodium hydroxide (2×500 mL), water(3×500 mL), dried over sodium sulfonate and concentrated to afford thetitle compound (221 g, 88%) as a clear oil. ¹H NMR (500 MHz, (CD₃)₂CO)δ: 7.81 (d, J=8.0 Hz, 2H), 7.49 (d, J=8.0 Hz, 2H), 4.14-4.19 (m, 2H),3.63-3.68 (m, 2H), 3.49-3.53 (m, 2H), 3.39-3.44 (m, 2H), 3.26 (s, 3H),3.47 (s, 3H).

Example 3

FIG. 3 is a synthetic scheme for the preparation of2-(2-(2-methoxyethoxy)ethoxy)-1,3-dimethylbenzene.

2-(2-(2-Methoxyethoxy)ethoxy)-1,3-dimethylbenzene

Dimethylformamide (200 mL) was added to sodium hydride (18 g as 60weight percent in oil, 450 mmol) under nitrogen. Next,2,6-dimethylphenol (50 g, 409 mmol) in dimethylformamide (100 mL) wasadded drop-wise and heated to 50° C. where 2-(2-methoxyethoxy)ethyl4-tosylate (113 g, 413 mmol) in dimethylformamide (200 mL) was addeddrop-wise and stirred overnight. The reaction mixture was diluted withmethyl tert-butyl ether (1 L) and washed with water (1 L). The waterlayer was back extracted with methyl tert-butyl ether (500 mL) and thecombined organics washed with 1M potassium hydroxide (3×300 mL),hydrochloric acid (1 weight percent, 2×500 mL), water (2×500 mL), brine(1×250 mL), dried over sodium sulfate and concentrated to afford thetitle compound (90.5 g, 90%) as a clear oil. ¹H NMR (300 MHz, (CD₃)₂CO)δ: 6.99 (d, J=7.8 Hz, 2H), 6.88 (t, J=7.8 Hz, 1H), 3.90-3.94 (m, 2H),3.75-3.80 (m, 2H), 3.64-3.68 (m, 2H), 3.50-3.54 (m, 2H), 3.31 (s, 3H),2.26 (s, 6H).

Example 4

FIG. 4 is a synthetic scheme for the preparation of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-dibenzothiophen-5-iumiodide.

5-(4-(2-(2-Methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-dibenzothiophen-5-iumiodide

Eaton's Reagent (60 mL) was added to a solution of dibenzothiopheneoxide (20.0 g, 0.1 mol) and2-(2-(2-methoxyethoxy)ethoxy)-1,3-dimethylbenzene (24.7 g, 0.11 mol) indichloromethane (60 mL) at 0° C., warmed to room temperature and stirredovernight. The reaction mixture was cooled to 0° C. and slowly quenchedby the addition of water (300 mL) and washed with methyl tert-butylether (2×250 mL). The organic layer is discarded and sodium iodide (30g, 0.200 mmol) in water (100 mL) was added to the aqueous layer undervigorous stirring. The precipitate was filtered and washed with copiousamounts of water, suspended in minimal acetone, stirred at roomtemperature for 1 hour and filtered to afford the title compound (30.2g, 57%) as an off-white solid. ¹H NMR (500 MHz, (CD₃)₂SO) δ: 8.52 (d,J=8.0 Hz, 2H), 8.33 (d, J=8.0 Hz, 2H), 7.96 (t, J=7.5 Hz, 2H), 7.75 (d,J=7.5 Hz, 2H), 7.31 (s, 2H), 3.94 (vis t, J=5.5 Hz, 2H), 3.67 (vis t,J=5.0 Hz, 2H), 3.55 (vis t, 6.0 Hz, 2H), 3.42 (vis t, J=4.5 Hz, 2H),3.21 (s, 3H), 2.20 (s, 6H).

Example 5

FIG. 5 is a synthetic scheme for the preparation of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

5-(4-(2-(2-Methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate

5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-dibenzothiophen-5-iumiodide (13.0 g, 24.3 mmol) and triethylammonium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (8.22 g, 24.8 mmol) weredissolved in dichloromethane (150 mL) and water (150 mL) and stirred atroom temperature overnight. The layers were separated and the organiclayer was washed with water (8×150 mL) and concentrated under reducedpressure to afford the title compound (15.1 g, 97%) as a whitehydroscopic solid which was stored under inert nitrogen atmosphere. ¹HNMR (500 MHz, (CD₃)₂CO) δ: 8.52 (d, J=8.0 Hz, 2H), 8.38 (d, J=8.5 Hz,2H), 8.00 (t, J=7.5 Hz, 2H), 7.80 (t, J=8.0 Hz, 2H), 7.51 (s, 2H),6.13-6.16 (m, 1H), 5.67-5.69 (m, 1H), 4.77 t, J=15.5 Hz, 2H), 4.02-4.05(m, 2H0, 3.73-3.77 (m, 2H), 3.58-3.62 (m, 2H), 3.44-3.49 (m, 2H), 3.25(s, 3H), 2.26 (s, 6H), 1.13 (s, 3H).

Example 6

FIG. 6 is a synthetic scheme for the preparation of5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

5-(4-Methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-(((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate

5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiopheniumchloride (37.8 g, 47.4 mmol and N,N,N-trimethyl-1-phenylmethanaminium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (18.9 g, 49.8 mmol) weredissolved in DCM (250 mL) and water (250 mL) and stirred at 25° C.overnight. The layers were separated, the aqueous phase extracted withdichloromethane (100 mL), the combined organic layers washed with water(8×200 mL) and concentrated under reduced pressure to afford the titlecompound (36.0, 77%) as an off white solid. ¹H NMR (500 MHz, (CD₃)₂CO)δ: (8.52-8.56 (m, 2H), 8.37 (d, J=8 Hz, 1H), 8.31 (d, J=8.5 Hz, 1H),7.99-8.06 (m, 2H), 7.78-7.85 (m, 3H), 7.63 (dd, J=9, 1.5 Hz, 1H), 7.31(d, J=9 Hz, 1H), 6.16-6.19 (m, 1H), 5.64-6.69 (m, 1H), 5.62 (s, 2h),4.72-4.79 (m, 2H), 4.50-4.65 (m, 2H), 4.42-4.47 (m, 1H), 3.96 (s, 3H),2.99-3.07 (m, 1H), 2.63-2.70 (m, 1H), 2.10-2.30 (m, 4H), (1.42-2.09 (m,31H).

Example 7

FIG. 7 is a synthetic scheme for the preparation of5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate.

5-(4-Methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(41R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate

5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiopheniumchloride (40.0 g, 50.2 mmol) and N,N,N-trimethyl-1-phenylmethanaminium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate (23.0 g, 52.6mmol) were dissolved in dichloromethane (300 mL) and water (300 mL) andstirred at room temperature overnight. The layers were separated, theorganic phase washed with water (7×250 mL) and concentrated to affordthe title compound (43.4 g, 83%) as a white solid. ¹H NMR (300 MHz,(CD₃)₂SO) δ: 8.52 (d, J=7.8 Hz, 2H), 8.31 (d, J=8.1 Hz, 1H), 8.26 (d,J=8.1 Hz, 1H), 7.97 (t, J=7.8 Hz, 2H), 7.75 (t, J=7.8 Hz, 2H), 7.71 (d,J=2.4 Hz, 1H), 7.35 (dd, J=9.0, 2.4 Hz, 1H), 7.22 (d, J=9.0 Hz, 1H),6.12-6.17 (m, 1H), 5.76-5.82 (m, 1H), 4.87 (s, 2H), 4.63 (t, J=15.6 Hz,2H), 4.59 (s, 2H), 4.35 (t, J=7.5 Hz, 1H), 3.82 (s, 3H), 2.92-3.10 (m,2H), 2.56-2.68 (m, 1H), 1.35-2.25 (m, 36H).

Example 8

FIG. 8 is a synthetic scheme for the preparation of5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

5-(4-Methoxy-3-(2-(2-(41R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate

5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-iumchloride (40.0 g, 59.2 mmol) and N,N,N-trimethyl-1-phenylmethanaminium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (23.6 g, 62.2 mmol) weredissolved in dichloromethane (300 mL) and water (300 mL) and stirred atroom temperature overnight. The layers were separated, the organic phasewashed with water (7×250 mL), concentrated to half volume andprecipitated into methyl tert-butyl ether (1.5 L). The precipitate wasfiltered, washed with methyl tert-butyl ether (2×500 mL) and dried toafford the title compound (39.1 g, 76%) as a white solid. ¹H NMR (300MHz, (CD₃)₂SO) δ: 8.53 (d, J=7.8 Hz, 2H), 8.34 (d, J=8.1 Hz, 2H), 8.27(d, J=7.8 Hz, 2H), 7.97 (t, J=7.5 Hz, 2H), 7.75 (dt, J=7.8, 2.7 Hz, 1H),7.68 (d, J=1.8 Hz, 1H), 7.38 (dd, J=9.0, 2.1 Hz, 1H), 7.23 (d, J=9.0 Hz,1H), 6.12 (vis s, 1H), 5.77 (vis s, 1H), 4.64 (t, J=15.6 Hz, 2H), 4.60(s, 2H), 4.25 (d, J=7.2 Hz, 1H), 4.05-4.21 (m, 2H), 3.82 (s, 3H),3.36-3.51 (m, 2H), 2.14-2.20 (m, 1H), 1.38-2.04 (m, 17H).

Example 9

In general polymer molecular weight were determined from ¹³C NMR spectraobtained on a Varian 300 Megahertz NMR spectrometer operating with arelaxation delay of 2 seconds by integration of initiator end groups andone of the carbons of the PAG unit.

FIG. 9 is a synthetic scheme for the preparation of a homopolymer of5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

Homopolymer of5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate

5-(4-methoxy-3-(4-((2-methyladamantan-2-yl)oxy)-1-(2-((2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-dibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (10.0 g, 10.2 mmol) wasdissolved in ethyl lactate/gamma-butyrolactone (3/7 v/v, 15.0 g). Theinitiator 2,2′-azobis(2.4-dimethyl valeronitrile) (1.00 g) was dissolvedin acetonitrile/tetrahydrofuran (2/1 v/v, 1.00 g). The monomer andinitiator solutions were added drop-wise over 4 hours to a flaskpreheated to 80° C. followed by an initiator chase. The reaction mixturewas stirred for 2 hours, cooled to room temperature, diluted withmethanol (17 g) and precipitated into diisopropyl ether (800 g). Thepolymer was filtered and dried to afford the title compound (8.00 g,80%, weight average molecular weight 3,972 daltons) as a white solid.

Example 10

FIG. 10 is a synthetic scheme for the preparation of a homopolymer of5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate.

Homopolymer of5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(41R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate

5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate (1.00 g,0.953 mmol) was dissolved in ethyl lactate/gamma-butyrolactone (3/7 v/v,1.50 g). 2,2′-Azobis(2.4-dimethyl valeronitrile) (0.150 g) was dissolvedin acetonitrile/tetrahydrofuran (2/1 v/v, 0.150 g). The monomer andinitiator solutions were added drop-wise to a flask preheated to 75° C.and stirred for 8 h. The reaction mixture was cooled to roomtemperature, diluted with acetone (0.900 g) and precipitated as a stickysolid from acetone/diisopropylether (1:1 25.0 g), decanted, redissolvedin acetone (2.40 g) and methanol (0.500 g) and precipitated intodiisopropyl ether (20× reaction volume). The polymer was filtered anddried to afford the title compound (0.550 g, 55%, weight averagemolecular weight 3,000 daltons) as a white solid.

Example 11

FIG. 11 is a synthetic scheme for the preparation of a homopolymer of5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

Homopolymer of5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate

5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (15.0 g, 17.3 mmol) wasdissolved in ethyl lactate/gamma-butyrolactone (3/7 v/v, 60.0 g).2,2′-Azobis(2.4-dimethyl valeronitrile) (2.25 g) was dissolved inacetonitrile/tetrahydrofuran (2/1 v/v, 2.25 g). The monomer andinitiator solutions were added drop-wise over 4 hours to a flaskpreheated to 90° C. The reaction mixture was cooled to room temperature,diluted with tetrahydrofuran (10× reaction volume) and acetone (5×reaction volume) and precipitated into diisopropyl ether (2000 g). Thepolymer was filtered and dried to afford the title compound (7.96 g,53%, weight average molecular weight 3,476 daltons) as a white solid.

Example 12

FIG. 12 is a synthetic scheme for the preparation of a copolymer of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate and5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate.

Copolymer of5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate and5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate

5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (3.00 g, 8.25 mmol) and5-(4-methoxy-3-(4-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-1-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-1,4-dioxobutan-2-yl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(2-(methacryloyloxy)acetoxy)ethanesulfonate (7.00 g, 6.67mmol) were dissolved in ethyl lactate/gamma-butyrolactone (3/7 v/v, 15.0g). 2,2′-Azobis(2.4-dimethyl valeronitrile) (1.50 g) was dissolved inacetonitrile/tetrahydrofuran (2/1 v/v, 1.50 g). The monomer andinitiator solutions were added drop-wise to a flask preheated to 75° C.over 4 hours. The reaction mixture was cooled to room temperature,precipitated as a sticky solid from methanol/diisopropyl ether (1:1, 20×reaction volume), redissolved into acetone (20.0 mL) and methanol (0.300g) and reprecipitated from diisopropyl ether/methanol (19:1 v/v, 2000mL), filtered and dried to afford the title compound (6.00 g, 60%,weight average molecular weight 2,500 daltons) as a white solid.

Example 13

FIG. 13 is a synthetic scheme for the preparation of a copolymer5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate and5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate.

Copolymer5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate and5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate

5-(4-(2-(2-methoxyethoxy)ethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (4.50 g, 12.4 mmol) and5-(4-methoxy-3-(2-(2-(((1R,3S,5r,7r)-2-methyladamantan-2-yl)oxy)-2-oxoethoxy)-2-oxo-1-(2-oxotetrahydrofuran-3-yl)ethyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (10.5 g, 12.1 mmol) weredissolved in ethyl lactate/gamma-butyrolactone (3/7 v/v, 60.0 g).2,2′-Azobis(2.4-dimethyl valeronitrile) (2.25 g) was dissolved inacetonitrile/tetrahydrofuran (2/1 v/v, 2.25 g). The monomer andinitiator solutions were added drop-wise to a flask preheated to 75° C.over 4 h. The reaction mixture was cooled to room temperature, dilutedwith tetrahydrofuran (5× reaction volume) and acetone (5× reactionvolume), precipitated from diisopropyl ether (20× reaction volume),filtered and dried to afford the title compound (11.0 g, 73%, weightaverage molecular weight 2,700 daltons) as a white solid.

Example 14 Preparation of Tetrapolymer with Acid Generator Units

A heel solution was made by dissolving 2-phenylpropan-2-yl methacrylate(0.39 g), 2-oxotetrahydrofuran-3-yl methacrylate (0.33 g),3,5-bis(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)cyclohexylmethacrylate (0.57 g) and5-(4-(2-(1-ethylcyclopentyloxy)-2-oxoethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (0.31 g) in 12.81 gethyl lactate/gamma butyrolactone (7/3 v/v). Feed solution was preparedby dissolving 2-phenylpropan-2-yl methacrylate (185.54 g, 0.967 mol),2-oxotetrahydrofuran-3-yl methacrylate (204.27 g, 1.26 mol),3,5-bis(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)cyclohexylmethacrylate (127.98 g, 0.29 mol) and5-(4-(2-(1-ethylcyclopentyloxy)-2-oxoethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (81.5 g, 0.132 mol) in606 g ethyl lactate:γ-butyrolactone (30/70 v/v). Initiator solution wasprepared by dissolving 65.96 g initiator (2,2′-azobis(2.4-dimethylvaleronitrile)) in 66 g acetonitrile/tetrahydrofuran (2/1 v/v). Thepolymerization was carried out in a 2 L 3-neck round bottom flask fittedwith a water condenser and a thermometer to monitor the reaction in theflask. The contents were stirred using an overhead stirrer. The reactorwas charged with the heel solution and the contents were heated to 75°C. The feed solution and the initiator solution were fed into thereactor using syringe pump over a 4 hour time period. The contents werethen stirred for additional 2 hours, whereby, the reaction was quenchedusing hydroquinone (2.0 g). The contents were cooled to room temperatureand precipitated twice out of 10× (by weight) diisopropyl ether/methanol95/5 (w/w). The polymer obtained was dried under vacuum after eachprecipitation step at 50° C. for 24 hours to yield 500 g polymer havinga weight average molecular weight of 5,200 daltons, a dispersity of 1.5,and a monomer composition of the respective monomers of 36.0 molepercent, 47.5 mole percent, 11.0 mole percent, and 5.5 mole percent.

Example 15 Preparation of Tetrapolymer with Acid Generator Units

The process of Example 14 was repeated, except that equimolar5-phenyl-5H-dibenzo[b,d]thiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate was used in place of5-(4-(2-(1-ethylcyclopentyloxy)-2-oxoethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate. The polymer obtainedhad a weight average molecular weight of 6,300 daltons, a dispersity of1.4, and respective monomer contents of 36.5 mole percent, 47.5 molepercent, 12.0 mole percent, and 5 mole percent.

Example 16 Preparation of Tetrapolymer with Acid Generator Units

The process of Example 14 was repeated, except that equimolar5-(4-(tert-butyl)phenyl)-5H-dibenzo[b,d]thiophen-5-ium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate was used in place of5-(4-(2-(1-ethylcyclopentyloxy)-2-oxoethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate. The polymer obtainedhad a weight average molecular weight of 5,200 daltons, a dispersity of1.6, and respective monomer contents of 34 mole percent, 51 molepercent, 9 mole percent, and 6 mole percent.

Example 17 Preparation of Tetrapolymer with Acid Generator Units

The process of Example 14 was repeated, except that an equimolar amountof the monomer of Example 9 was used in place of5-(4-(2-(1-ethylcyclopentyloxy)-2-oxoethoxy)-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate. The polymer obtainedhad a weight average molecular weight of 5,200 daltons, a dispersity of1.5, and respective monomer contents of 38 mole percent, 46 molepercent, 10 mole percent, and 6 mole percent.

Example 18 Preparation of Tetrapolymer with Acid Generator Units

A heel solution was made by dissolving 2-phenylpropan-2-yl methacrylate(0.53 g), (1S,3R,8S)-5-oxo-4-oxatricyclo[4.3.1.13,8]undecan-1-ylmethacrylate (0.44 g),3,5-bis(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)cyclohexylmethacrylate (0.78 g) and phenyldibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (0.42 g) in 20.0 g ethyllactate/gamma butyrolactone (7/3 v/v). Feed solution was prepared bydissolving 2-phenylpropan-2-yl methacrylate (7.50 g),(1S,3R,8S)-5-oxo-4-oxatricyclo[4.3.1.13,8]undecan-1-yl methacrylate(12.23 g),3,5-bis(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)cyclohexylmethacrylate (4.97 g) and phenyldibenzothiophenium1,1-difluoro-2-(methacryloyloxy)ethanesulfonate (1.12 g) in 26.0 g ethyllactate:γ-butyrolactone (3/7 v/v). Initiator solution was prepared bydissolving 2.59 g initiator (2,2′-azobis(2.4-dimethyl valeronitrile)) in2.59 g acetonitrile/tetrahydrofuran (2/1 v/v). The polymerization wascarried out in a 200 mL 3-neck round bottom flask fitted with a watercondenser and a thermometer to monitor the reaction in the flask. Thecontents were stirred using an overhead stirrer. The reactor was chargedwith the heel solution and the contents were heated to 75° C. The feedsolution and the initiator solution were fed into the reactor usingsyringe pump over a 4 hour time period. The contents were then stirredfor additional 2 hours, whereby, the reaction was quenched usinghydroquinone (0.200 g). The contents were cooled to room temperature andprecipitated twice out of 10× (by weight) diisopropyl ether/methanol95/5 (w/w). The polymer obtained was dried under vacuum after eachprecipitation step at 50° C. for 24 hours to yield 26 grams of polymerhaving a weight average molecular weight of 5,000 daltons, a dispersityof 1.5, and respective monomer contents of 36 mole percent, 47 molepercent, 12 mole percent, and 5 mole percent.

Example 19 Preparation and Processing of a Photoresist Composition

Non-polymeric photoacid generators and photo-destroyable quenchers(collectively, “additives”) used in the preparation of photoresistcompositions are summarized in Table 1. Photoresist compositions aresummarized in Table 2. The Example 19 positive-tone photoresistcomposition was prepared by combining component 1, 5.33 g of a 10 weightpercent solution of the polymer of Example 17 in ethyl lactate;component 2, 10.373 g of a 2 weight percent solution of the additive A-1in ethyl lactate; component 3, 0.320 g of a 0.5 weight percent solutionof tetrakis(2-hydroxypropyl)ethylenediamine in ethyl lactate; component4, 0.356 g of a 2 weight percent solution of the additive A-2 in ethyllactate; component 5, 0.107 g of a 0.5 weight percent solution offluorinated surfactant (Omnova PF656) in ethyl lactate; component 6,4.737 g of ethyl lactate; and component 7, 8.775 g of2-hydroxyisobutyric acid methyl ester. The formulated resist was passedthrough a 0.01 micrometer (μm) polytetrafluoroethylene (PTFE) filter.The thus prepared resist was spin coated onto a silicon wafer, softbaked to remove carrier solvent and exposed through a photomask to EUVradiation. The imaged resist layer was then baked at 110° C. for 60seconds and then developed with an aqueous alkaline composition.

TABLE 1 Additive Structure A-1

A-2

A-3

A-4

For Table 2, below, components 1-7 correspond to the descriptions inExample 19. Component amounts, in brackets, are expressed in units ofgrams.

TABLE 2 Comp. 1 Comp. 2 Comp. 3 Comp. 4 Comp. 5 Comp. 6 Comp. 7 Ex.(polymer) (PAG) (quencher) (PDQ) (surfactant) (solvent) (solvent) 19 Ex.17 A-1 [0.320] A-2 [0.107] [4.737] [8.775] (C) [5.33] [10.37] [0.356] 20Ex. 16 A-1 [0.563] A-2 [0.188] [9.826] [14.63] (C) [9.378] [14.79][0.626] 21 Ex. 18 — [0.247] — [0.165] [26.61] [14.75] (C) [8.229] 22 Ex.14 A-3 [13.31] — [1.109] [48.17] [87.75] (C) [55.43] [94.24] 23 Ex. 9 —[2.467] — [0.197] [24.64] [11.70] (I) [0.987]* 24 Ex. 10 — [0.513] —[0.041] [4.903] [2.388] (I) [0.205]* 25 Ex. 11 — [0.617] — [0.049][6.162] [2.925] (I) [0.247]* 26 Ex. 12 — [0.617] — [0.049] [6.162][2.925] (I) [0.247]* 27 Ex. 11 — [0.704] Ex. 1 [0.235] [21.25] [17.64](I) [15.64]** [4.543]*** 28 Ex. 12 — [0.938] Ex. 1 [0.313] [33.54][23.52] (I) [15.64] [6.057]*** 29 Ex. 13 — [0.938] Ex. 1 [0.313] [33.54][23.52] (I) [15.64] [6.057]*** 30 Ex. 16 A-4 [0.472] Ex. 1 [0.157][9.296] [11.70] (C) [7.867] [9.745] [0.762]*** 31 Ex. 15 — [0.478] —[0.318] [25.76] [17.52] (C) [15.92] *Added as solid. **Added as 7.50weight percent solution in ethyl lactate. ***Added as 0.5 weight percentin ethyl lactate.

Critical Dimension Uniformity.

Critical dimension uniformity (CDU) is the calculated 3 Sigma (threestandard deviations) for ten Fields of View (FOV) measuring 36 contactholes for each FOV, all taken at Best Exposure/Best Focus at 30 nmcontact hole resolution with 1:1 half pitch. Each data point has beenpre-normalized to a standard EUV photoresist which is run in eachlithographic slot to eliminate variability and noise. The results,presented in Table 3, show that the lowest (best) CDU value is exhibitedby the inventive Example 23 photoresist. In Table 3, the CDU of Example23 is normalized to 1, and designated with “⋄”. Comparative exampleswhich underperform relative to the example by 0-5% are designatedwith“●”; comparative examples which underperform relative to the exampleby 5%-15% are designated with “▪”; and comparative examples whichunderperform relative to the example by >15% are designated with “□”. InTable 3, “PolyPAG” refers to a polymer comprising 50 to 100 mole percentof photoacid-generating repeat units, “Polymer-bound-PAG” refers to apolymer comprising photoacid-generating repeat units in an amount lessthan 50 mole percent, and “free PAG” refers to a non-polymer-boundphotoacid-generator.

TABLE 3 Relative Example PAG Type CDU Example 23 PolyPAG ⋄ ComparativeExample 19 Polymer-bound-PAG + free PAG □ Comparative Example 31Polymer-bound-PAG □ Comparative Example 22 Polymer-bound-PAG + free PAG□ Comparative Example 20 Polymer-bound-PAG + free PAG ▪

Dose to Clear.

Extreme ultraviolet (EUV) dose to clear was measured as the dose at 5%remaining film thickness. Data was collected either on a Litho TechJapan (LTJ) EVUES-9000 tool or on the Albany MET tool at the College ofNanoscale Science and Technology at the State University of New York,Albany. Processing conditions were a soft bake at 110° C. for 90seconds, a post exposure bake for at 100° C. for 60 seconds, anddevelopment for 30 seconds at room temperature in 0.26 Ntetramethylammonium hydroxide developer.

Dose to clear results are summarized in Table 4. Dose to clear valuesfor inventive Examples 23-26 are normalized to a value of 1.00 forComparative Example 21. Values below 1.00 represent a desirable decreasein dose to clear energy. The results show that inventive photoresistcompositions 23-26 exhibit substantially decreased dose to clearenergies relative to the Example 21 comparison. The results areconsistent with the hypothesis that a progression from polymer-bound-PAGto (polymer-bound-PAG+additive PAG) to polyPAG will result in anincreased sensitivity due to PAG density and uniformity.

TABLE 4 Example PAG Type Normalized E₀ Comparative Example 21Polymer-bound-PAG 1.00 Example 23 PolyPAG 0.69 Example 24 PolyPAG 0.64Example 25 PolyPAG 0.61 Example 26 PolyPAG 0.54

In Table 5, inventive Examples 27-29 are normalized to a value of 1.00for Comparative Example 31. Values below 1.00 represent a desirabledecrease in dose to clear energy. The results show that inventivephotoresist compositions 27-29 exhibit decreased dose to clear energiesrelative to the Example 31 comparison. The results are again consistentwith the hypothesis that a progression from polymer-bound-PAG to polyPAGwill result in an increased sensitivity due to PAG density anduniformity.

TABLE 5 Example PAG Type Normalized E₀ Comparative Example 31Polymer-bound-PAG 1.00 Example 27 PolyPAG 0.83 Example 28 PolyPAG 0.69Example 29 PolyPAG 0.97

Contrast Slope.

EUV contrast slope was measured as the slope of the contrast curvebetween 95% and 5% film thickness during positive tone development. Datawas collected either on a Litho Tech Japan (LTJ) EVUES-9000 tool or onthe Albany MET tool at the College of Nanoscale Science and Technologyat the State University of New York, Albany. Processing conditions werea soft bake at 110° C. for 90 seconds, a post-exposure bake for at 100°C. for 60 seconds, and development for 30 seconds at room temperature in0.26 N tetramethylammonium hydroxide developer. In Table 6 the contrastslope of Comparative Example 30 was normalized to 1.00, and designatedwith “⋄”. Inventive examples that outperform relative to the comparativeexample by 10%-20% are designated with “▪”; and inventive examples thatoutperform relative to the comparative example by >20% are designatedwith “□”. The results show that for the property of contrast slope,inventive Example 27 outperforms Comparative Example 30 by at least 10%,and inventive Examples 28 and 29 outperform Comparative Example 30 by atleast 20%.

TABLE 6 Relative Examples PAG Type Contrast Slope Comparative Example 30Polymer-bound-PAG + ⋄ free PAG Example 27 PolyPAG ▪ Example 28 PolyPAG □Example 29 PolyPAG □

In Table 7, the contrast slope of Comparative Example 19 was normalizedto 1, and designated with “⋄”. Inventive examples that outperform thecomparative example by >20% are designated with “□”. The results showthat for the property of contrast slope, inventive Example 23-26outperform Comparative Example 21 by at least 20%. The results areconsistent with the hypothesis that a progression from polymer-bound-PAGto polyPAG will result in greater (more negative) contrast slope.

TABLE 7 Relative Example PAG Type Contrast Slope Comparative Example 21Polymer-bound-PAG ⋄ Example 23 PolyPAG □ Example 24 PolyPAG □ Example 25PolyPAG □ Example 26 PolyPAG □

The invention claimed is:
 1. A polymer comprising, based on 100 molepercent of total repeat units, 60 to 100 mole percent ofphotoacid-generating repeat units, wherein each of thephotoacid-generating repeat units comprises (a) photoacid-generatingfunctionality and (b) base-solubility-enhancing functionality selectedfrom the group consisting of tertiary carboxylic acid esters, secondarycarboxylic acid esters wherein the secondary carbon is substituted withat least one unsubstituted or substituted C₆₋₄₀ aryl, acetals, ketals,lactones, sultones, alpha-fluorinated esters, beta-fluorinated esters,alpha,beta-fluorinated esters, polyalkyleneglycols, alpha-fluorinatedalcohols, and combinations thereof: wherein the photoacid-generatingrepeat units have the structure

wherein R¹ is independently in each of the repeat units H, F, —CN, C₁₋₁₀alkyl, or C₁₋₁₀ fluoroalkyl; L¹ is independently in each of the repeatunits —O—, —C(O)—O—, unsubstituted C₆₋₁₈ arylene, or substituted C₆₋₁₈arylene; m is independently in each of the repeat units 0 or 1; L² isindependently in each of the repeat units an unsubstituted orsubstituted C₁₋₂₀ hydrocarbylene, wherein the substituted C₁₋₂₀hydrocarbylene can, optionally, include one or more in-chain divalentheteroatom-containing groups that is —O—, —S—, —NR², —PR²—, —C(O)—,—OC(O)O—, —N(R²)C(O)—, —C(O)N(R²)—, —OC(O)N(R²)—, —N(R²)C(O)O—, —S(O)—,—S(O)₂—, —N(R²)S(O)₂—, —S(O)₂N(R²)—, —OS(O)₂—, or —S(O)₂O—, wherein R²is H or C₁₋₁₂ hydrocarbyl; Z⁻ is independently in each of the repeatunits sulfonate (—SO₃ ⁻), sulfonamidate, which is an anion ofsulfonamide, —S(O)₂N—R³, wherein R³ is H or unsubstituted or substitutedC1-12 hydrocarbyl, or sulfonimidate, which is an anion of sulfonamide,—S(O)₂N⁻ S(O)₂R³, wherein R³ is H or unsubstituted or substituted C1-12hydrocarbyl; and Q⁺ is photoacid-generating cation; wherein at least oneof L¹, L² (when m is 1), and Q⁺ comprises the base-solubility-enhancingfunctionality.
 2. The polymer of claim 1, comprising 95 to 100 molepercent of the photoacid-generating repeat units.
 3. The polymer ofclaim 1, wherein the photoacid-generating repeat units are derived froma single monomer.
 4. The polymer of claim 1, wherein thephotoacid-generating repeat units are derived from at least twodifferent monomers.
 5. The polymer of claim 1, wherein thebase-solubility-enhancing functionality is a tertiary carboxylic acidester, an acetal, a ketal, a lactone, or a combination thereof.
 6. Aphotoresist composition comprising the polymer of claim 1 and a solvent.7. A method of forming an electronic device, comprising: (a) applying alayer of the photoresist composition of claim 6 on a substrate; (b)pattern-wise exposing the photoresist composition layer to activatingradiation; and (c) developing the exposed photoresist composition layerto provide a resist relief image.